1 Senn, Information Technology, 3rd Edition© 2004 Pearson Prentice Hall

James A. Senn’sInformation Technology, 3rd Edition

Chapter 7

Enterprise Databases and Data Warehouses

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Objectives

• Identify the reasons organizations choose to share databases and the functions of a database management system.

• Explain the difference between relational and object-oriented databases and their uses in business.

• Describe the differences between schemas, views, and indexes.

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Objectives (Continued)

• Discuss the benefits of client/server computing.

• Differentiate between shared and distributed databases.

• Explain why enterprises establish data warehouses and how they differ from data marts and enterprise databases.

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Objectives (Continued)

• Distinguish between a database administrator and a system programmer.

• Discuss database administration procedures and concurrency procedures and explain why these are an essential part of a shared database system.

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The Principles of Data SharingDefinition

• Database: A collection of data and information describing items of interest to an organization.

• Entity: A person, place, thing, event or condition about which data and information are collected.

• Enterprise Database: A collection of data designed to be shared by many users within an organization.

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The Principles of Data SharingDefinition (Continued)

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The Principles of Data SharingDatabase Management Systems

• Database Management Systems (DBMS): A program that makes it possible for users to manage the data in a database in order to increase accessibility and productivity.

• The Functions of Database Management:– Integrating Databases– Reducing Redundancy– Sharing Information– Maintaining Integrity– Enabling Database Evolution

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The Principles of Data SharingDatabase Management Systems (Continued)

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Enterprise Database StructuresEnterprise Data Model

• Enterprise Data Model/Entity Relationship: A graphical representation of the items (the entities) of interest about which data is captured and stored in the database.

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Enterprise Database StructuresEnterprise Data Model (Continued)

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Enterprise Database StructuresSchema

• Schema: The structure of a database.

• Schema for Relational Database– Relational Database: A database in which

the data are structured in a table format consisting of rows and columns.

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Enterprise Database StructuresSchema (Continued)

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Enterprise Database StructuresSchema (Continued)

• Schema for Object-Oriented Database– Object-oriented Database: A database that

stores data and information about objects.– Object: A component that contains data

about itself and how it is to be processed.– Action/Method: An instruction that tells a

database how to process an object to produce specific information.

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Enterprise Database StructuresSchema (Continued)

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Enterprise Database StructuresViews

• View: A subset of one or more databases, created either by extracting copies of records from a database or by merging copies of records from multiple databases.

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Enterprise Database StructuresViews (Continued)

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Enterprise Database StructuresIndexes

• Index: A data file that contains identifying information about each record and its location in storage.

• Record Key: In a database, a designated field used to distinguish one record from another.

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Enterprise Database StructuresIndexes (Continued)

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Client/Server ComputingDefinition

• File Server: A computer containing files that are available to all users interconnected on a local area network.

• Client/Server Computing: A type of computing in which all data and information retrieval requests and responses pass over a network. Much of the processing is performed on the server and the results of the processing are transmitted to the client.

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Client/Server ComputingDefinition (Continued)

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Client/Server ComputingDefinition

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Client/Server ComputingDefinition (Continued)

• Client: In client-server computing, a desktop workstation.

• Server: A computer that hosts a network and provides the resources that are shared on the network.

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Client/Server ComputingThe Benefits of Client/Server Computing

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Databases on the InternetDefinition

• Web-based Integration: Makes data from enterprise databases available to users connecting through the Internet (including enterprise intranets and extranets).

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Databases on the InternetDefinition (Continued)

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Distributed DatabasesDefinition

• Shared Database: A database shared among many users and applications.

• Distributed Database: A database that resides in more than one system in a distributed network. Each component of the database can be retrieved from any node in the network.

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Distributed DatabasesPartitioning and Replication

• Partitioning: A method of database distribution in which different portions of the database reside at different nodes in the network.

• Replication: A method of database distribution in which one database contains data that are included in another database.

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Distributed DatabasesDistribution Strategies

• Geographic Distribution Strategy: A database distribution strategy in which the database is located in a region where the data and information are used most frequently.

• Functional Distribution Strategy: A database distribution strategy in which the database is distributed according to business functions.

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Distributed DatabasesDesigned a Distributed Database

• Database Directory: The component of a shared database that keeps track of data and information.

• Other Design Factors– Storage Costs– Processing Costs– Communication Costs– Retrieval and Processing– Reliability– Frequency of Updates and Queries

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Distributed DatabasesDesigned a Distributed Database (Continued)

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Data Warehouses and OLAPDefinition

• Online Analytical Processing (OLAP): Database processing that selectively extracts data from different points of view.

• Data Warehouse: A large data store, designed from inquiries, that combines details of both current and historical operations, usually drawn from a number of sources.

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Data Warehouses and OLAPComparison of Enterprise Databases and Data Warehouses

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Data Warehouses and OLAPData Warehouse

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Data Warehouses and OLAPDefinition

• Data Mining: Uses software designed to detect information hidden in the data.

• Data Marts: Processed to focus on a specific area of activities or isolated scientific or commercial processes.

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PeopleDefinition

• Database Administrator (DBA): The IT professional responsible for managing all the activities and procedures related to an organization’s database.

• Systems Programmer

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ProceduresDatabase Administration Procedures

• Database Administration Procedures: The procedures associated with managing a database.– Database Planning– Database Design– Database Creation– Database Maintenance– Analysis of Usage– Creation and Monitoring of Security

Procedures

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ProceduresConcurrency Procedures

• Concurrent Data Sharing: A database procedure that allows several users to access the database simultaneously.

• Nonconcurrent Data Sharing: A database procedure that allows individuals to access a database only when no other person or application is processing the data.

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ProceduresConcurrency Procedures (Continued)

• Record Locking: A concurrency procedure that prohibits another user from accessing or altering a records that is in use.

• File Locking: Used in systems that store unstructured information and have file-level sharing.

• Deadlock: A situation in which each user of a database is waiting for the others to unlock a record.